The Second Generation of Phyrexian Praetors (DMU, NEO, SNC, ONE) Urabrask, Heretic Praetor Jin-Gitaxias, Progress Tyrant Elesh Norn, Mother of Machines Vorinclex, Monstrous Raider Sheoldred, the Apocalypse The Phyrexian praetors have a good ability for you and deny a good ability from your opponent in a mirrored way (e.g.: buff your creatures, shrink theirs, double your counters, halve their counters)
When it comes to using counterspells, it's better to use them to stop cards resolving on your opponents' side rather than keeping your own stuff safe
With the powerful card Perfectly Ultimate Great Moth being an ideal result of this, its easy to see how these decks can gain powerful advantages
Each hero has their own deck and a cool flip mechanic that lets you switch between hero and alter-ego